Area Calculator
Find the area of 2D shapes or the surface area of 3D solids. Useful for design and coursework.
Sphere area
Formula: Sphere: S = 4πr²
Cube area
Formula: Cube: S = 6a²
Cylinder area
Formula: Cylinder: S = 2πr² + 2πrh
Cone area
Formula: Cone: S = πr² + πr√(r² + h²)
Rectangular prism area
Formula: Rectangular prism: S = 2(lw + lh + wh)
Triangle area
Formula: Triangle: S = (b × h) / 2
About area
Area is the amount of surface, in square units (m², cm², etc.), whether flat (2D) or on a 3D solid.
Choose the shape that matches your figure, then apply the correct formulae.
Area formulae
Square: S = a²
Rectangle: S = L × w
Triangle: S = (b × h) / 2
Circle: S = πr²
Sphere: S = 4πr²
Cylinder: S = 2πr² + 2πrh
Cone: S = πr² + πr√(r² + h²)
Cube: S = 6a²
Units
Measure every length in one unit (e.g. all cm or all m).
- 1 m² = 10,000 cm².
- 1 km² = 1,000,000 m².
- 1 ha = 10,000 m².
- 1 are = 100 m².
Example results
Square: a=6 → S=36 cm².
Rectangle: 5 × 7 → S=35 cm².
Triangle: b=6, h=4 → S=12 cm².
Circle: r=4 → S≈50.27 cm².
Where it’s useful
- Floor space, garden or land area.
- Estimating paint, tiles or fabric.
- Sizing solar panels or packaging.
Tips
- Complicated shape? Split it into simpler shapes and add the areas.
- Unit mix-up? Convert everything to the same unit first.
- Need the working? The main solver on the home page shows the full method.